transcriptional regulation in prokaryotes

four elements that make up a prokaryotic gene

promoter, transcription start site, coding region, terminator

A technique for identifying the site within a region of DNA to which a specific DNA-binding protein binds

dna footprinting

the most commonly observed bases when aligning sequences

consensus sequence

main technique chip-seq uses to separate proteins

immunoprecipitation

which strand, and direction, are consensus sequences given as?

sense, five to three

write the consensus sequence for bacterial promoters

TTGACA(N17)TATAAT

____ promoters have a high rate of transcriptional initiation and tend to

have a good fit to the consensus

strong

____ promoters have a low rate of transcriptional initiation and tend to

have a poorer fit to the consensus sequence

weak

Promoter strength is ____ to how well a specific promoter

sequence aligns to the consensus sequence

proportional

promoter mutation that decreased rna synthesis

down mutation

promoter mutation that increases rna synthesis

up mutation

what is a holoenzyme

core enzyme plus sigma factor

reduce RNA Pol-promoter interactions or block RNA polymerase.

repressors

increase RNA polymerase activity or its interactions with the promoters

activators

(ligand) can bind to repressor/activator and induce a conformational change that increase or decrease its activity.

Effectors

in the absence of any regulatory factors, the gene is transcribed (on).

negative regulation

Control involves a repressor that inhibits transcription only under certain conditions.

negative regulation

Control involves an activator that increases the ability of RNA polymerase to bind to promoter

postitive regulation

In the absence of any regulatory factors, the gene is not transcribed or transcribed weakly.

positive regulation

how many promoters do operons use

one

a cluster of genes sharing a promoter and regulatory sequences

operon

the binding sequence for transcriptional regulators

operator

what causes the trp repressor to activate and shut down the operon operator

tryptophan

what does tryptophan do to the repressor to turn off the operon

conformational change

regulation of an enzyme by binding of an effector/ ligand molecule

allosteric effect

When trp is ____, trp binds the trp repressor protein to produce a structure that CAN bind the DNA via helix turn helix

high

When trp is _____:—helix turn helix structure is different because there isno tryptophan bound to the protein, repressor protein DOES NOT bind DNA

low

does the lac operon make a lot of enzymes in the presence of abundant glucose?

no

three lac genes that make up the lac operons

z, y, a

what binds to the lac operon repressor

allolactose

do bacteria prefer glucose or lactose for metabolism

glucose

Transcription of the lac operon requires both the presence of ___ and absence of ____

lactose, glucose

does the lac operon use positive or negative regulation

both

what does high cAMP levels activate

binding of CAP

where does CAP bind

promoter